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<div class="titlepage"><div><div><h4 class="title">
<a name="beast.ref.boost__beast__file_mode"></a><a class="link" href="boost__beast__file_mode.html" title="file_mode">file_mode</a>
</h4></div></div></div>
<p>
        <a class="indexterm" name="idm66821"></a>
      </p>
<p>
        File open modes.
      </p>
<h5>
<a name="beast.ref.boost__beast__file_mode.h0"></a>
        <span class="phrase"><a name="beast.ref.boost__beast__file_mode.synopsis"></a></span><a class="link" href="boost__beast__file_mode.html#beast.ref.boost__beast__file_mode.synopsis">Synopsis</a>
      </h5>
<p>
        Defined in header <code class="literal">&lt;<a href="../../../../../../boost/beast/core/file_base.hpp" target="_top">boost/beast/core/file_base.hpp</a>&gt;</code>
      </p>
<pre class="programlisting"><span class="keyword">enum</span> <span class="identifier">file_mode</span>
</pre>
<h5>
<a name="beast.ref.boost__beast__file_mode.h1"></a>
        <span class="phrase"><a name="beast.ref.boost__beast__file_mode.values"></a></span><a class="link" href="boost__beast__file_mode.html#beast.ref.boost__beast__file_mode.values">Values</a>
      </h5>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                <p>
                  Name
                </p>
              </th>
<th>
                <p>
                  Description
                </p>
              </th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">read</span></code>
                </p>
              </td>
<td>
                <p>
                  Random read-only access to an existing file.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">scan</span></code>
                </p>
              </td>
<td>
                <p>
                  Sequential read-only access to an existing file.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">write</span></code>
                </p>
              </td>
<td>
                <p>
                  Random reading and writing to a new or truncated file.
                </p>
                <p>
                  This mode permits random-access reading and writing for the specified
                  file. If the file does not exist prior to the function call, it
                  is created with an initial size of zero bytes. Otherwise if the
                  file already exists, the size is truncated to zero bytes.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">write_new</span></code>
                </p>
              </td>
<td>
                <p>
                  Random reading and writing to a new file only.
                </p>
                <p>
                  This mode permits random-access reading and writing for the specified
                  file. The file will be created with an initial size of zero bytes.
                  If the file already exists prior to the function call, an error
                  is returned and no file is opened.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">write_existing</span></code>
                </p>
              </td>
<td>
                <p>
                  Random write-only access to existing file.
                </p>
                <p>
                  If the file does not exist, an error is generated.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">append</span></code>
                </p>
              </td>
<td>
                <p>
                  Appending to a new or truncated file.
                </p>
                <p>
                  The current file position shall be set to the end of the file prior
                  to each write.
                </p>
                <p>
                  @li If the file does not exist, it is created.
                </p>
                <p>
                  @li If the file exists, it is truncated to zero size upon opening.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">append_existing</span></code>
                </p>
              </td>
<td>
                <p>
                  Appending to an existing file.
                </p>
                <p>
                  The current file position shall be set to the end of the file prior
                  to each write.
                </p>
                <p>
                  If the file does not exist, an error is generated.
                </p>
              </td>
</tr>
</tbody>
</table></div>
<h5>
<a name="beast.ref.boost__beast__file_mode.h2"></a>
        <span class="phrase"><a name="beast.ref.boost__beast__file_mode.description"></a></span><a class="link" href="boost__beast__file_mode.html#beast.ref.boost__beast__file_mode.description">Description</a>
      </h5>
<p>
        These modes are used when opening files using instances of the <span class="emphasis"><em>File</em></span>
        concept.
      </p>
<h5>
<a name="beast.ref.boost__beast__file_mode.h3"></a>
        <span class="phrase"><a name="beast.ref.boost__beast__file_mode.see_also"></a></span><a class="link" href="boost__beast__file_mode.html#beast.ref.boost__beast__file_mode.see_also">See
        Also</a>
      </h5>
<p>
        <a class="link" href="boost__beast__file_stdio.html" title="file_stdio"><code class="computeroutput"><span class="identifier">file_stdio</span></code></a>
      </p>
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<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie
      Falco<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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